MR dampers in smart structures with nonlinear non-affine dynamics improvising intelligent control

University of Technology, Sydney. Faculty of Engineering and Information Technology.The increasing complexity of high-rise buildings, cable-stayed long-span bridges, deep-sea offshore structures or suspension systems demands effective tools for control and health monitoring. These infrastructure systems are usually integrated with actuation, sensing, computation resources and information networks, taking advantage of the synergy of civil engineering and mechatronics in an emerging area called civiltronics. Towards the achievement of high performance smart structures, semi-active vibration control in complex civil structures has been very promising, particularly in the mitigation of external excitations and dynamic loadings owing to its meritorious features of low cost, strong robustness and high reliability against various loading sources. Structural behavior and energy efficiency can be improved via directly controlling the input of the smart devices. For example, semi-active controlled dampers, from the dissipation point of view by using suitable control schemes for parameterized relationships describing the system dynamics of the structure integrated with the smart devices with respect to the applied electrical signal. This research is concerned with the problem of controlling the nonlinear, non-affine dynamics of smart structures with magneto-rheological (MR) dampers. A laboratorial set-up of a one-storey steel frame and a benchmark five-storey building model integrated with MR dampers are used in this research. These smart structures are subject to scaled earthquake vibrations excited by a shake table. A static hysteresis model is adopted for the MR damper, in which current-dependent nonlinear functions are used to represent the damper force-velocity characteristics. Here the semi-active control problem of the smart structure system is formulated in current-input non-affine nonlinear state space equations. The complications in the design are tackled by using intelligent control, whereby adaptive fuzzy logic control is proposed to deal with nonlinearity of the control dynamics and non-affinity in the control input, assuming the availability of the displacement and velocity information of the last floor. Here, self-organising adaptive fuzzy logic control is developed to prevent cases that the resulting fuzzy inference system may be unnecessarily large or too small to adequately represent the complex dynamics of the smart structure under control. The main objectives of this research are thus to model the overall smart structure system and to develop self-organising adaptive fuzzy logic schemes for the continuous-time multiple-input multiple-output uncertain nonlinear dynamics of the structure. The proposed control algorithms are implemented in MATLAB and SIMULINK. To illustrate their effectiveness in seismic vibration suppression of civil structures due to earthquake excitations, simulation results are presented together with discussions on performance evaluation and further remarks on the implementation aspects

A review of routing protocols in wireless body area networks

Recent technological advancements in wireless communication, integrated circuits and Micro-Electro-Mechanical Systems (MEMs) has enabled miniaturized, low-power, intelligent, invasive/ non-invasive micro and nano-technology sensor nodes placed in or on the human body for use in monitoring body function and its immediate environment referred to as Body Area Networks (BANs). BANs face many stringent requirements in terms of delay, power, temperature and network lifetime which need to be taken into serious consideration in the design of different protocols. Since routing protocols play an important role in the overall system performance in terms of delay, power consumption, temperature and so on, a thorough study on existing routing protocols in BANs is necessary. Also, the specific challenges of BANs necessitates the design of new routing protocols specifically designed for BANs. This paper provides a survey of existing routing protocols mainly proposed for BANs. These protocols are further classified into five main categories namely, temperature based, cross-layer, cluster based, cost-effective and QoS-based routing, where each protocol is described under its specified category. Also, comparison among routing protocols in each category is given. © 2013 ACADEMY PUBLISHER

Lithiation and electrophilic substitution of dimethyl triazones

The lithiation and electrophilic substitution of dimethyl triazones is described. Directed lithiation or tin–lithium exchange of dimethyl triazones afforded the corresponding dipole stabilized nucleophiles that were trapped with various electrophiles. Keto-triazone derivatives accessed by acylation of such nucleophiles were readily converted into the corresponding imidazolone heterocycles.National Institutes of Health (U.S.) (National Institute of General Medical Sciences (U.S.) GM074825

Exploiting unknown dynamics in communications amongst coexisting wireless body area networks

© 2015 IEEE. In this paper, we propose a prediction algorithm for dynamic channel allocation amongst coexisting Wireless body area networks (WBANs). Variations in channel assignment due to mobility scenarios within each WBAN as well as the movement of WBANs towards each other is investigated. The proposed scheme is further optimized to allocate the optimum transmission time with synchronous and parallel transmissions such that interference is fully avoided. This reduces the number of interfering nodes and leads to better usage of the scarce limitation of resources in these networks, larger network lifetime, higher energy savings and higher throughput. In fact, the aim of this protocol is to mitigate interference along with maintaining minimum power consumption in order to maximize network lifetime and increase the spatial reuse and throughput of each WBAN. Simulation results show that our approach achieves a much higher spatial reuse using the smart spectrum allocation scheme for interference mitigation in collocated WBANs. We conduct extensive simulations for coexistence prediction in different mobility scenarios using the NS-2 simulator. Consequently, we demonstrate the efficiency of the proposed protocol in providing interference-free channel assignments and higher energy savings

Reduction in ischemic brain injury following the administration of pentoxifylline after transient global ischemia/reperfusion in a rat model

Background: It is well known that the hippocampus, the CA1 Pyramidal cells in particular, is selectively vulnerable during global cerebral ischemia. Recently, it is observed that pentoxifylline has a neuroprotective effect. This study explored the pharmacological relationship between ischemiainduced cell death of the hippocampus and the efficacy of a vasodilator agent (pentoxifylline) in the prevention of delayed neuronal death. Methods: This experimental study was performed on 4 groups: control, ischemia, experimental (200mg/kg pentoxifylline injection one hour prior to and one hour following ischemia) and vehicle (normal saline). Transient global ischemia was induced by bilateral common carotid arteries occlusion. To investigate the apoptotic bodies and caspase-3 activities as a central role in the execution phase of apoptosis, the brains were prepared for the TUNEL technique. Results: Pentoxifylline administration limited apoptosis and caspase-3 activities in rats' hippocampi. Our data showed no significant difference between the number of apoptotic bodies in the CA1 region of the hippocampus in the control and pentoxifylline -treated groups (p= 0.994). The results of one- way ANOVA revealed that that ischemia significantly increased caspase-3 levels in the hippocampus (p< 0.05); however, the level of caspase-3 in pentoxifylline -treated rats was less than the ischemic group. Conclusion: These results suggest that the neuroprotective effect of pentoxifylline (200mg/kg) may be accompanied by a reduction in ischemic damage within the CA1 region of the hippocampus in rats subjected to transient global cerebral ischemia

Effect of Cyperus rotundus on ischemia-induced brain damage and memory dysfunction in rats

Objective(s): Global cerebral ischemia-reperfusion injury causes loss of pyramidal cells in CA1 region of hippocampus. In this study, we investigated the possible neuroprotective effects of the ethanol extract of Cyperus rotundus (EECR) on a model of global transient ischemia in rat, by evaluating the pathophysiology of the hippocampal tissue and spatial memory. Materials and Methods: Treatment group (EECR, 100 mg/kg/day) was gavaged from 4 days before, to 3 days after ischemia. Morris water maze test was performed 1 week after ischemia for 4 days. Brain tissue was prepared for Nissl staining. Results: Our data showed no statistical difference between the treatment and ischemia groups in water maze task. So, treatment of ischemia with EECR cannot improve spatial learning and memory. On the contrary EECR ameliorated the CA1 pyramidal cell loss due to transient global ischemia/ reperfusion injury. Conclusion: These results suggest that EECR cannot reduce the ischemia-induced, cognitive impairments seen after transient, global cerebral ischemia but can prevent pyramidal cell loss in CA1 region of hippocampus. © 2015, Mashhad University of Medical Sciences. All rights reserved

C7-Derivatization of C3-Alkylindoles Including Tryptophans and Tryptamines

A versatile strategy for C7-selective boronation of tryptophans, tryptamines, and 3-alkylindoles by way of a single-pot C2/C7-diboronation–C2-protodeboronation sequence is described. The combination of a mild iridium-catalyzed C2/C7-diboronation followed by an in situ palladium-catalyzed C2-protodeboronation allows efficient entry to valuable C7-boroindoles that enable further C7-derivatization. The versatility of the chemistry is highlighted by the gram-scale synthesis of C7-boronated N-Boc-L-tryptophan methyl ester and the rapid synthesis of C7-halo, C7-hydroxy, and C7-aryl tryptophan derivatives.National Institute of General Medical Sciences (U.S.) (GM089732)National Institute of General Medical Sciences (U.S.) (GM074825)National Science Foundation (U.S.) (CHE-1205646

Biogenetically-Inspired Total Synthesis of Epidithiodiketopiperazines and Related Alkaloids

Natural products chemistry has historically been the prime arena for the discovery of new chemical transformations and the fountain of insights into key biological processes. It remains a fervent incubator of progress in the fields of chemistry and biology and an exchange mediating the flow of ideas between these allied fields of science. It is with this ethos that our group has taken an interest in and pursued the synthesis of a complex family of natural products termed the dimeric epipolythiodiketopiperazine (ETP) alkaloids. We present here an Account of the highly complex target molecules to which we pegged our ambitions, our systematic and relentless efforts toward those goals, the chemistry we developed in their pursuit, and the insight we have gained for their translational potential as potent anticancer molecules.National Institute of General Medical Sciences (U.S.) (Grant GM089732)Amgen Inc

Protective effect of pentoxifylline on male wistar rat testicular germ cell apoptosis induced by 3,4-methylenedioxymeth amphetamine

Objective(s): 3, 4-methylenedioxymethamphetamine (MDMA) one of the methamphetamine derivatives that affect the reproductive system, has not been well understood. Many young people are consumers of drugs such as MDMA that can affect their reproductive capability. Apoptosis is the main mechanism for male infertility. Pentoxifylline (PTX) increases cAMP intracellularly and reduces tumor necrosis factor-α. This study aimed to investigate the protective effect of PTX administration in MDMA-induced apoptosis in testes of male Wistar rats. Materials and Methods: Thirty male Wistar rats weighing 250-300 g were randomly divided into five groups: control group (without any intervention), group receiving 7.5 mg/kg MDMA three times every two hours for one day, first experimental group receiving 100 mg/kg PTX just at the time of third injection of MDMA, second experimental group receiving 100 mg/kg PTX a week before MDMA administration, and the vehicle group, which received MDMA+saline. Two weeks later, testes were removed and prepared for H&E staining, TUNEL and Western blot techniques. Results: There was a significant decrease of the score in the MDMA group compared with the control group. In first and second experimental groups, the quality of seminiferous epithelium was improved compared with the MDMA group. The number of TUNEL-positive cells/tubule increased in MDMA and vehicle groups, which is decreased by administration of PTX before MDMA. Expression of active caspase-3 significantly increased in MDMA group, which is significantly decreased by administration of PTX before MDMA. Conclusion: PTX can significantly reduce the severity of lesions in the testes following administration of MDMA. © 2016, Mashhad University of Medical Sciences. All rights reserved

Comparison of ultrasound-guided supra-scapular plus Axillary nerve block with Interscalene block for postoperative pain management in arthroscopic shoulder surgery; a double-blinded randomized open-label clinical trial

Background: Post-arthroscopic shoulder surgery pain is severe enough to interfere with initial recovery and rehabilitation. Objectives:We aimed to evaluate the analgesic effects of postoperative ultrasound-guided suprascapular plus axillary nerve blocks superficial subepidermal axon bundles (SSAB) with interscalene block (ISB) in arthroscopic shoulder surgery. Methods: In this single-blind randomized, open-label clinical trial, 80 candidates of elective arthroscopic shoulder surgery were randomly allocated to receive either SSAB or ISB at a postoperative care unit. The severity of resting and changing position pain was measured using visual analogue scale (VAS) score at 4h, 8h, 12h, 16h, and 24h, postoperatively. Timing of first opioid request, 24h dose requirement, patients� satisfaction rate, and side effects were also recorded. All registered data were analyzed using SPSS software version 23 for Windows (SPSS, Chicago, IL). Results: Resting and changing position pain scores were comparable between SSAB and ISB groups in the most time intervals. At 12h, moving and resting pain was significantly lower in ISB than SSAB group, while moving pain was more severe in ISB group at 24h assessment. Patient satisfaction scores were comparable between the two groups except for 12h assessment. Time to first analgesic requirement and total dose of 24h opioid requirement were not significantly different between the two groups. Conclusions: Suprascapular plus axillary nerve block could be an effective and safe alternative for interscalene block for pain management after arthroscopic shoulder surgery. © 2021, Author(s)